php求解n位格雷码的输出

<?php

function getGray($n) {

// write code here

if(is_int($n)){

if ($n < 1) {

echo "格雷码长度必须大于等于1";

return null;

}

$strArr = array();

//返回1的格雷码

if ($n == 1) {

$strArr[0] = "0";

$strArr[1] = "1";

return $strArr;

}

else {

//$strArr1=array();

$strArr1 = getGray($n - 1);

for ($i = 0; $i < count($strArr1);$i++) {

$strArr[$i] = "0".$strArr1[$i];

}

for ($i =count($strArr1); $i < 2*count($strArr1);$i++) {

$strArr[$i] = "1".$strArr1[2*count($strArr1)-1-$i];

}

return $strArr;

}

}

else{

echo "请输入整型数值";}

}

header("content-type:text/html;charset=utf-8");

$arr=getGray(2.34);

print_r($arr);

?>